Bridge construction in guitar-like instruments



Jar l. 21, 1969 v. GAMBELLA ETAL 3,422,715

BRIDGE CONSTRUCTION IN GUITAR-LIKE INSTRUMENTS Filed NOV. 15, 1967|NVENTOR6 wnce/rf eZ/z M 7? aq zm z BY Jazz w I ATTORNEY United StatesPatent 3,422,715 BRIDGE CONSTRUCTION IN GUITAR-LIKE INSTRUMENTS VincentGambella, Tenafly, and Nathan I. Daniel, Deal,

N.J., assignors, by mesne assignments, to The Danelectro Corporation,Neptune City, N.J., a corporation of New York Filed Nov. 15, 1967, Ser.No. 683,180 US. Cl. 84307 Int Cl. GlOd 3/04 3 Claims ABSTRACT OF THEDISCLOSURE This invention relates to stringed musical instruments of theguitar type. In particular, it relates to a guitar-like instrument whichapparently originated in India and which is often referred to as asitar. This instrument produces somewhat of a buzzing sound as themelody is played. The buzz results from the use of a relatively widebridge against which the strings slap during the playing of theinstrument. This is, of course, far different from the function ofconventional bridges as found in various stringed instruments whereinthe bridge is very narrow and serves principally as a string support andseparator. The buzz has found high favor as an intriguing soundthroughout the history of sitar playing.

A good sitar often requires months in the making. While the usuallyoverall elaborate construction accounts largely for this time, aparticularly time-consuming factor is the production of the bridge. Thisis a most exacting task, requiring many hours of hand filing and shapingto achieve the necessary curved formation of the upper surface as Willbe explained hereinafter. Once completed, the sitar bridge is fixed inplace and is never thereafter tampered with, except by an expertcraftsman in that art.

According to this invnetion we have made possible the mass production ofsitar bridges which are moreover superior in operation to hand madebridges. Thus the bridge of this invention is sturdy, highly accurate,and most importantly, is easily adjustable. This itself is a new conceptin sitar bridges, which have classically been thought of as delicate andvirtually unchangeable or untouchable once finally installed in place.However, adjustability is very desirable as will be describedhereinafter.

The invention will be further understood from the following descriptionand drawings wherein:

FIGURE 1 is a perspective view of a guitar-like musical instrumentprovided with the sitar bridge;

FIGURE 2 is an enlarged, fragmentary, plan view of the bridge portion ofthe instrument;

FIGURE 3 is a cross-sectional view as taken along the lines 33 of FIGURE2;

FIGURE 4 is a front end elevational view of the bridge portion shown inFIGURE 2; and

FIGURE 5 is a substantially side elevational view of the bridge portionshown in FIGURE 2.

The general construction of the instrument as a whole may varyconsiderably. In the illustrated embodiment it comprises a body 10, aneck 11, a head 12, and strings Patented Jan. 21, 1969 13, all servingtheir conventional functions, as well as electronic amplifier pick-ups14 and control knobs 15, all as conventional. The instrument alsoincludes a series of pretuned, non-fingered strings 16 which aresometimes referred to as drone strings, since they are tuned to vibratespontaneously in sympathy with the sound waves produced in playing theinstrument, as will be understood by those skilled in the art. However,the player may if he likes strum across the series of non-fingeredstrings 16 for whatever effect he aspires to. Strings 16 have tuningscrews 17 generally factory-set and requiring a suitable tool foractuation.

The bridge 20 of this invention is interposed forwardly of theconventional tail section 21. In the form shown, the bridge comprises asubstantially rectangular molded phenolic body member 22, representativedimensions being as follows: Upper boss 23 has a front to rear width ofalmost 2 inches (specifically 1% inches in a satisfactory embodiment).The transverse width is about 2% inches, or enough to support the sixstrings 13. Integral with boss 23, and on a lower level therefrom areside wings 24. For example, the thickness or height of boss 23 may beabout inch, while the thickness of Wings 24 is about 3 inch.

Boss 23 has a central, rearward, two-diameter hole 25 forfastening tothe body 10 as by screw 26, while wings 24 have forward holes forfastening to the body 10 as by screws 28. The action of these screws isof importance as will be described hereinafter. From the underside ofboss 23, are formed two forward, transversely spaced, chambers 29 whichreceive biasing coil springs 30, the lower terminals of which are seatedin wells 31 formed in body 10. The action of these springs will bereferred to hereinafter.

Secured as by pins or adhesive to the rear wall of boss 23 is thevertical metal plate 32 having top grooves 33 for supporting andseparating the strings 13.

The front to rear conformation of boss 23 is of great importance. Asobserved in FIGURES 3 and 5, this conformation is not planar. On thecontrary, the front to rear surface, (1% inches as above set forth), isconvexly arcuate, the radius of curvature being about 4 inches.

FIGURE 3 shows the normal or rest position of the strings 13. It will beobserved that a considerable crest portion of about 1% inches or 22 /2degrees of arc is contacted by the string 13. As the string 13 isstrummed or plucked, almost the entire width, or about 26 degrees or somay be contacted by the string during a forceful excursion thereof. Ofcourse the string will also lift relative to the position of FIGURE 3 atanother period of its vertical excursions so that less than 22 /2degrees will then be contacted.

The relatively extended contact length between the strings 13 and thefront to rear slightly convex upper surface of boss 23 produces thecharacteristic and peculiar sitar or somewhat buzzing sound. Of course,that characteristics per se is not the subject of this invention becausethe classic hand produced bridge provides substantially the same soundas above explained. However, the particular form shown has markedadvantages as will hereinafter be further explained.

Theoretically the strings 13 may be considered to make tangentialcontact with the front to rear convex upper surface of boss 23, althoughthe normal resiliency of the strings produces a somewhat hugging actionto the extent where about 20 degrees or so are contacted as abovedescribed. However, assuming for purposes of explanation that thecontact is tangential, it will be recognized that each string iscontacted at the crest of the convex upper surface of boss 23. The axialposition of the crest is of great importance. In other words a sitarbridge should be positioned with respect to the length of the string sothat the said crest contacts the string at a particular point relativeto the string length. Specifically, and as a sitar or expert guitarplayer will know, the said contact point marks the effective length ofthe string and the distance therefrom to the twelfth fret of the guitarneck should be the same as the remaining distance to the nut 35. This isstandard guitar construction. Accordingly, it is highly desirable thatthe tangential contact point "be axially adjustable to compensate forguitar body deviations from precision measurements, either as originallyproduced or as the instrument ages.

In this invention, such axial adjustment along the length of theinstrument is accomplished by rocking and thus effectivelyre-positioning the bridge 20. It will be understood that as the bridgeis rocked fore and aft, the abovementioned crest will necessarily shiftaxially along the length of the instrument. This adjustment isaccomplished by loosening screws 28 and then playing center screw 26against bias springs 31 to accomplish the desired tilted position of thebridge 20. Thereafter, the screws 28 are re-tightened.

It will be recognized that as the center fastening screw 26 is Screwedin, the forward end of bridge 20 is forced upwardly by springs 30 tocause the bridge 20 to assume a new tilted position and thus effectre-adjustment. The opposite result is achieved by loosening or upwardlyrepositioning the screw 26.

We have shown a preferred embodiment of our invention, but it is obviousthat numerous changes and omissions may be made without departing fromits spirit.

What is claimed is:

1. The combination with a stringed instrument elongated body, of abridge therefor, said bridge being secured to said instrument body andhaving an upper surface width of more than one inch extending axially ofsaid elongated body, said upper surface being convexly arcuate alongsaid width and being disposed so as to support each of the strings ofsaid instrument body linearly along at least one inch of said convexlyarcuate surface, said convexly arcuate surface having a crest which,together with adjacent portions of said upper surface, supports saidstrings, means to substantially shift and re-position said crest axiallyof said instrument body so as to correspondingly vary the support areaof said strings by said bridge upper surface, said means tosubstantially shift and reposition said crest comprises means to rocksaid bridge on said instrument body so as to shift said crest along aline fore and aft of said elongated instrument body, locking means forlocking said bridge in its shifted position, said means to rock saidbridge comprising an adjustable screw penetrating one end of saidconvexly arcuate upper surface and securing said one end to saidinstrument body, and spring biasing means at the other end of saidconvexly arcuate upper surface whereby said spring biasing means mayrock said bridge when said adjustable screw is loosened.

2. The combination according to claim 1 and wherein said bridge has avertical metal plate secured to said bridge rearwardly of saidadjustable screw and being slotted to support said strings in separatedposition.

3. The combination according to claim 2 and wherein said adjustablescrew is centrally and rearwardly disposed on said bridge, and whereinsaid spring biasing means comprises two transversely spaced coil springsat the forward end of said bridge and disposed in respective wellsformed on the underside of said bridge and tending to urge said forwardend upwardly.

References Cited UNITED STATES PATENTS 2,196,531 4/1940 Larisch 84-299 X2,469,091 5/ 1949 Watts 84-307 2,573,254 10/1951 Fender 84307 2,714,3268/1955 McCarty 84299 3,014,395 12/1961 Blair 84312 RICHARD B. WILKINSON,Primary Examiner.

J. F. GONZALES, Assistant Examiner.

